Format: ORAL

Rafael P. Farias1, Lucas E. N. Costa2, Klaus Mehltreter3

1 Universidade Federal da Bahia, Bahia, Brazil. 2 Instituto Tecnológico Vale, Pará, Brazil. 3 Instituto de Ecología, Xalapa, Mexico.

For ferns, an abundant component of tropical understories, knowledge about their insect interactions and defense mechanisms is still very limited. Consequently, the ecological and evolutionary drivers of herbivory, as well as the ecological role of ferns in these interactions are overlooked. Here, we investigated ferninsect interactions in three different ecosystems asking the following questions: 1. How do ferns structure their defense mechanism (syndromes)? 2. Does the leaf damage of ferns differ from angiosperms in mangroves? 3. Are there herbivore effects on Pteridium after fire events? Our sample included 34 species of ferns from the Atlantic Forest, Acrostichum aureumL. (and two angiosperm species) in the mangroves, and Pteridium in burnt ironstone campo rupestre. We measured some leaf traits for our first (SLA, water content, trichome density, nitrogen, phosphorus, alkaloids, phenols, saponins, tannins and triterpenoids) and second question (phenols). Leaf damages were estimated by relative leaf area loss per plant and species. All traits were correlated with each other and compared with leaf damages. We identified three different defense syndromes: (I) high nutritional quality combined with a variable trichome density (14 species), (II) low nutritional quality, but high phenol concentrations, and often high trichome density (4), and (III) intermediate nutritional quality combined with a low trichome density or no trichomes (16). Leaf damages ranged between 0 and 32.3% but did not differ among defense syndromes. Acrostichum aureum had lower phenol concentrations than the angiosperms mangrove species, but was damaged than Rhizophora mangle. Postfire resprouts of Pteridium were highly damaged by herbivores (almost 75%). We conclude that ferns combine a variety of defensive traits against insects, with a similar resistance against insects, that ferns can exhibit similar damages than angiosperms in mangroves; and that Pteridium may constitute a crucial resource for herbivores after fire events.